What if we took a recursive approach and built a smallest possible robot?
Lost Article and Found Articles

MIT Review had an article on nanotechnology for disease eradication, DNA repair, and microsurgery in the 1990s that's probably somewhere among the thousands of entries resulting from a web search of, "MIT Review nanotechnology cell repair," or the few hundred resulting from an academic article search for the same.1 The article I can't find described a recursive nano-robot scheme like the one described in this question.

What seems plausible given the current state of technology is to find a recursive algorithm that will command a 3D printer to make a smaller 3D printer that can print a still smaller one.

Extending the Normal Meaning of Recursion

The algorithm will have to take a step in capability beyond mere recursion.  It doesn't call itself.  It must load itself into the machine it printed and then boot the copy of itself there.  As it loads itself, at each level in size, it must parametrize its child for that geometrically reduced size for each progressive reduction.  It must stop when the desired size is achieved.

Such a paradigm could be called, "Printail Recursion," from the synthesis of, "Printer," and the algorithmic principle of, "tail recursion," from the dawn of LISP.

Applying the Decorator Pattern

Once Printail Recursion works, other robotic or algorithmic features could piggy back on the appropriate components of the progressive micro-children.



Notes

[1] The later of those two may even provide some departmental contacts to open options for partnering between academic institutions, something usually compelling for research oriented students and a great catalyst for scientific collaboration among the next generation of researchers.